Yes, you can see the time students spent on a quiz.
On the quiz's results page, switch to Detailed view at the top of the page. The grid below will expand to show some additional columns. One of these columns is called Quiz mins, and it shows how long the student spent on that attempt of the quiz, in minutes.
If a student took a break in the middle of a quiz or completed it over multiple days, we'll adjust their Quiz mins time so it doesn't include that inactive time.